Retrospective study of clinicopathological features and prevalence of germline pathogenic variants in male breast cancer

Male breast cancer (MaBC) is rare and data on its clinicopathological and germline characteristics are scarce. A retrospective study at two centers in Brazil included 106 patients diagnosed with MaBC between 2000 and 2022. Median age at diagnosis was 58.5 years (range 33-84), and 64% reported a family history of cancer. Invasive ductal carcinoma was the predominant histological subtype (88%). Most tumors were grade 2 or 3 (90%) and HR-positive (93%). HR-negative/HER2-positive disease was rare (1%), and TNBC accounted for 4% of cases. At diagnosis, 65% had stage II or III disease. Germline testing was performed in 55 patients, of whom 12 (22%) harbored pathogenic or likely pathogenic variants. The most frequently affected gene was BRCA2 (11%), followed by CHEK2 (5.5%), MUTYH (3.6%) and RAD51C (1.8%). The authors conclude that MaBC in this cohort was predominantly luminal, high-grade, and frequently diagnosed at advanced stages. The high prevalence of germline pathogenic variants supports broader implementation of genetic counseling and multigene testing in this population.